DOCSLIB.ORG

SPEN Induces Mir-4652-3P to Target HIPK2 in Nasopharyngeal Carcinoma

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
SPEN Induces Mir-4652-3P to Target HIPK2 in Nasopharyngeal Carcinoma Li et al. Cell Death and Disease (2020) 11:509 https://doi.org/10.1038/s41419-020-2699-2 Cell Death & Disease ARTICLE Open Access SPEN induces miR-4652-3p to target HIPK2 in nasopharyngeal carcinoma Yang Li1,YuminLv1, Chao Cheng2,YanHuang3,LiuYang1, Jingjing He1,XingyuTao1, Yingying Hu1,YutingMa1, Yun Su1,LiyangWu1,GuifangYu4, Qingping Jiang5,ShuLiu6,XiongLiu7 and Zhen Liu1 Abstract SPEN family transcriptional repressor (SPEN), also known as the SMART/HDAC1-associated repressor protein (SHARP), has been reported to modulate the malignant phenotypes of breast cancer, colon cancer, and ovarian cancer. However, its role and the detail molecular basis in nasopharyngeal carcinoma (NPC) remain elusive. In this study, the SPEN mRNA and protein expression was found to be increased in NPC cells and tissues compared with nonmalignant nasopharyngeal epithelial cells and tissues. Elevated SPEN protein expression was found to promote the pathogenesis of NPC and lead to poor prognosis. Knockdown of SPEN expression resulted in inactivation ofPI3K/AKT and c-JUN signaling, thereby suppressing NPC migration and invasion. In addition, miR-4652-3p was found to be a downstream inducer of SPEN by targeting the homeodomain interacting protein kinase 2 (HIPK2) gene, a potential tumor suppressor that reduces the activation of epithelial–mesenchymal transition (EMT) signaling, thereby reducing its expression and leading to increased NPC migration, invasion, and metastasis. In addition, SPEN was found to induce miR-4652-3p expression by activating PI3K/AKT/c-JUN signaling to target HIPK2. Our data provided a new molecular mechanism for SPEN as a metastasis promoter through activation of PI3K/AKT signaling, thereby stimulating the c-JUN/miR-4652-3p axis to target HIPK2 in NPC. 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; Introduction cause of treatment failure3. Accordingly, understanding Nasopharyngeal carcinoma (NPC) is highly prevalent in the molecular mechanisms by of invasion and/or metas- Southern China with a much higher incidence than tasis of NPC is critical for the identification of novel elsewhere1. It is characterized by high invasion and early therapeutic targets and formulation of better treatment metastasis. Patients with NPC are often diagnosed at strategies. advanced stage of the disease2. Although regional control In previous studies, several genes have been reported to – has been greatly improved by the advances in radio- be involved in NPC metastasis4 6. SPEN family tran- therapy and chemotherapy, metastasis remains the major scriptional repressor (SPEN), also known as SMART/ HDAC1-associatedrepressor (SHARP), is a large nuclear protein that plays an important role in transcriptional Correspondence: Xiong Liu ([email protected])or regulation and inactivation of chromosome X7. Legare Zhen Liu ([email protected]) et al. reported that the inactivation of SPEN may con- 1Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein tribute to breast tumor progression and thus suggested Modification and Degradation, State Key Laboratory of Respiratory Disease, SPEN as a tumor suppressor in ERα-positive breast can- School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou cers8. In contrast, Feng et al. found that SPEN (SHARP) 510095 Guangdong, China 2Department of Pediatric Otorhinolaryngology, Shenzhen Key Laboratory of gene acts as a candidate oncogene, promoting the Viral Oncology, The Clinical Innovation & Research Centre, Shenzhen Hospital, pathogenesis of human hematopoietic malignancies, Southern Medical University, Shenzhen, Guangdong, China breast and colon cancer9. Furthermore, Liu et al. Full list of author information is available at the end of the article These authors contributed equally: Yang Li, Yumin Lv, Chao Cheng, Yan Huang demonstrated that SPOCD1(SPEN) may act as a Edited by G. Calin © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a linktotheCreativeCommons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Official journal of the Cell Death Differentiation Association Li et al. Cell Death and Disease (2020) 11:509 Page 2 of 12 carcinogenesis factor by activating the PI3K/AKT path- SPEN through the activation of PI3K/AKT/c-JUN sig- way to restrained cell apoptosis in Ovarian cancer (OC)10. naling. In addition, miR-4652-3p was found to directly These studies suggested that SPEN played a significant target HIPK2 to participate in the SPEN-mediated pro- and complexed role in tumor pathogenesis. However, the motion of NPC migration, invasion, and metastasis. molecular alterations and biological functional involve- ment of SPEN in the pathogenesis of NPC have not been Results investigated. SPEN expression and clinicopathological characteristics in MicroRNAs (miRNAs) area class of small (17–23 NPC nucleotides) noncoding RNAs that silence mRNA mole- To determine the role of SPEN in NPC development, its cules through a degradation or translational inhibition expression level was analyzed in various NPC cell lines process. They participate in various biological processes, (HONE1, SUNE1, 5-8F, 6-10B, CNE1, and CNE2) and – including tumorigenesis and metastasis11 13. Multiple immortalized nasopharyngeal epithelial (NP) cell lines miRNAs have been found to play key roles in regulating (NP69 and SXSW-1489) by quantitative real-time poly- the expression of various critical genes during the devel- merase chain reaction (qRT-PCR) analysis. The endo- opment of human tumors4,14,15. Several of them were genous mRNA level of SPEN in all six NPC cell lines was identified as regulators of the progression of NPC, such as significantly upregulated compared with that in SXSW- miR-374a, miR-184, and miR-31886,16,17. However, the 1489 nonmalignant immortalized NP cells, although the regulation of miRNAs involving SPEN has not been difference between NPC cells and NP69 nonmalignant NP reported to date. cells (Fig. 1a) was not significant. As for protein level, a This study reports a newly discovered miRNA, namely large cohort of 238 NPC tissues and 54 nonmalignant miR-4652-3p, as an oncogenic regulator miRNA, which NP tissues were examined by immunohistochemistry was found to be upregulated by the potential oncogene (IHC) analysis. SPEN expression displayed nuclear and Fig. 1 Elevated expression of SPEN promoted the poor prognosis of NPC patients. a mRNA levels of SPEN analyzed by qRT-PCR assays in six human NPC cell lines (HONE1, SUNE1, 5–8F, 6-10B, CNE1, CNE2) and immortalized normal nasopharyngeal epithelial cell lines NP69 and SXSW-1489. b Representative IHC images of SPEN expression in NP and NPC tissues. a, b: weak expression of SPEN in NP samples; c, d: strong and positive expression of SPEN in NP samples; e, f: weak staining of SPEN in NPC specimens; g, h: strong and positive staining of SPEN in NPC specimens. (original magnification ×400). c Kaplan–Meier survival curve for overall survival in NPC patients based on SPEN expression level (P = 0.0305, log-rank test). Official journal of the Cell Death Differentiation Association Li et al. Cell Death and Disease (2020) 11:509 Page 3 of 12 Table 1 The expression of SPEN in NPC compared with SPEN induces miR-4652-3p expression in NPC cells NP tissues. To investigate the downstream effector miRNAs regu- lated by SPEN, an Affymetrix 3.0 miRNA array was used Group Cases (n) SPEN expression χ2 P* value to examine the differential expression of miRNAs between HONE1-siSPEN and HONE1-NC cells (Fig. 3a). High Low Expression analysis by qRT-PCR confirmed that miR- expression expression 4652-3p expression was downregulated by twofold or NPC 238 141 (59.2%) 97 (40.8%) 29.234 0.000 more at the mRNA level in SPEN-silenced HONE1 cells compared with HONE1-NC group (Fig. 3b). NP 54 10 (18.5%) 44 (81.5%) NPC nasopharyngeal carcinoma, NP nasopharyngeal epithelium. MiR-4652-3p promotes NPC cell metastasis in vitro and *χ2 test was applied to assess the expression of SPEN in NPC and NP in vivo HONE1 and 5–8F cells successfully transfected with cytoplasmic distribution patterns in both NPC and NP miR-4652-3pmimics were used to investigate the effects cells with different expression levels (Fig. 1b). Statistical of miR-465-3p on migration and invasion alterations analysis confirmed that among the 238 NPC specimens, in vitro. First, qRT-PCR analysis showed the expression 97 (40.8%) had low SPEN expression and 141 (59.2%) had level of miR-4652-3p was higher in HONE1 and 5–8F high SPEN expression. Instead, among the 54 NP tissues, cells transfected with miR-4652–3p mimics than that in low SPEN-expressing tissues accounted for 44 (81.5%), cells transfected with NC (Fig. 3c). In addition, over- and high SPEN-expressing tissues accounted for 10 expression of miR-4652-3p in HONE1 and 5–8F cells (18.5%). In addition, NPC tissues showed higher SPEN greatly promoted cell migration and invasion abilities (Fig. expression level than NP tissues(P < 0.001, Table 1). In 3d, e). In addition, we established two NPC cell lines addition, the analysis of the relationship between SPEN stably overexpressing miR-4652–3p, namely HONE1-LV- expression and the clinicopathological characteristics in miR-4652-3p and 5-8F-LV-miR-4652-3p, by lentivirus- patients with NPC revealed no statistically significant mediated transfection and used them for in vivo studies.
Load more

Recommended publications
  • HIPK2–P53ser46 Damage Response Pathway Is Involved in Temozolomide-Induced Glioblastoma Cell Death Yang He, Wynand P
    Published OnlineFirst February 22, 2019; DOI: 10.1158/1541-7786.MCR-18-1306 Cell Fate Decisions Molecular Cancer Research The SIAH1–HIPK2–p53ser46 Damage Response Pathway is Involved in Temozolomide-Induced Glioblastoma Cell Death Yang He, Wynand P. Roos, Qianchao Wu, Thomas G. Hofmann, and Bernd Kaina Abstract Patients suffering from glioblastoma have a dismal prog- in chromatin-immunoprecipitation experiments, in which nosis, indicating the need for new therapeutic targets. Here p-p53ser46 binding to the Fas promotor was regulated by we provide evidence that the DNA damage kinase HIPK2 HIPK2. Other pro-apoptotic proteins such as PUMA, and its negative regulatory E3-ubiquitin ligase SIAH1 are NOXA, BAX, and PTEN were not affected in HIPK2kd, and critical factors controlling temozolomide-induced cell also double-strand breaks following temozolomide remain- death. We show that HIPK2 downregulation (HIPK2kd) ed unaffected. We further show that downregulation of significantly reduces the level of apoptosis. This was not the HIPK2 inactivator SIAH1 significantly ameliorates the case in glioblastoma cells expressing the repair protein temozolomide-induced apoptosis, suggesting that the MGMT, suggesting that the primary DNA lesion responsible ATM/ATR target SIAH1 together with HIPK2 plays a pro- 6 for triggering HIPK2-mediated apoptosis is O -methylguanine. apoptotic role in glioma cells exhibiting p53wt status. A Upon temozolomide treatment, p53 becomes phosphory- database analysis revealed that SIAH1, but not SIAH2, is lated whereby HIPK2kd had impact exclusively on ser46, significantly overexpressed in glioblastomas. but not ser15. Searching for the transcriptional target of p-p53ser46, we identified the death receptor FAS (CD95, Implications: The identification of a novel apoptotic APO-1) being involved.
    [Show full text]
  • Updates on HIPK2: a Resourceful Oncosuppressor for Clearing Cancer Gabriella D’Orazi1,2*, Cinzia Rinaldo2,3 and Silvia Soddu2*
    D’Orazi et al. Journal of Experimental & Clinical Cancer Research 2012, 31:63 http://www.jeccr.com/content/31/1/63 REVIEW Open Access Updates on HIPK2: a resourceful oncosuppressor for clearing cancer Gabriella D’Orazi1,2*, Cinzia Rinaldo2,3 and Silvia Soddu2* Abstract Homeodomain-interacting protein kinase 2 (HIPK2) is a multitalented protein that exploits its kinase activity to modulate key molecular pathways in cancer to restrain tumor growth and induce response to therapies. HIPK2 phosphorylates oncosuppressor p53 for apoptotic activation. In addition, also p53-independent apoptotic pathways are regulated by HIPK2 and can be exploited for anticancer purpose too. Therefore, HIPK2 activity is considered a central switch in targeting tumor cells toward apoptosis upon genotoxic damage and the preservation and/or restoration of HIPK2 function is crucial for an efficient tumor response to therapies. As a proof of principle, HIPK2 knockdown impairs p53 function, induces chemoresistance, angiogenesis, and tumor growth in vivo,onthe contrary, HIPK2 overexpression activates apoptotic pathways, counteracts hypoxia, inhibits angiogenesis, and induces chemosensitivity both in p53-dependent and -independent ways. The role of HIPK2 in restraining tumor development was also confirmed by studies with HIPK2 knockout mice. Recent findings demonstrated that HIPK2 inhibitions do exist in tumors and depend by several mechanisms including HIPK2 cytoplasmic localization, protein degradation, and loss of heterozygosity (LOH), recapitulating the biological outcome obtained by RNA interference studies in tumor cells, such as p53 inactivation, resistance to therapies, apoptosis inhibition, and tumor progression. These findings may lead to new diagnostic and therapeutic approaches for treating cancer patients. This review will focus on the last updates about HIPK2 contribution in tumorigenesis and cancer treatment.
    [Show full text]
  • Mithramycin Represses Basal and Cigarette Smoke–Induced Expression of ABCG2 and Inhibits Stem Cell Signaling in Lung and Esophageal Cancer Cells
    Cancer Therapeutics, Targets, and Chemical Biology Research Mithramycin Represses Basal and Cigarette Smoke–Induced Expression of ABCG2 and Inhibits Stem Cell Signaling in Lung and Esophageal Cancer Cells Mary Zhang1, Aarti Mathur1, Yuwei Zhang1, Sichuan Xi1, Scott Atay1, Julie A. Hong1, Nicole Datrice1, Trevor Upham1, Clinton D. Kemp1, R. Taylor Ripley1, Gordon Wiegand2, Itzak Avital2, Patricia Fetsch3, Haresh Mani6, Daniel Zlott4, Robert Robey5, Susan E. Bates5, Xinmin Li7, Mahadev Rao1, and David S. Schrump1 Abstract Cigarette smoking at diagnosis or during therapy correlates with poor outcome in patients with lung and esophageal cancers, yet the underlying mechanisms remain unknown. In this study, we observed that exposure of esophageal cancer cells to cigarette smoke condensate (CSC) led to upregulation of the xenobiotic pump ABCG2, which is expressed in cancer stem cells and confers treatment resistance in lung and esophageal carcinomas. Furthermore, CSC increased the side population of lung cancer cells containing cancer stem cells. Upregulation of ABCG2 coincided with increased occupancy of aryl hydrocarbon receptor, Sp1, and Nrf2 within the ABCG2 promoter, and deletion of xenobiotic response elements and/or Sp1 sites markedly attenuated ABCG2 induction. Under conditions potentially achievable in clinical settings, mithramycin diminished basal as well as CSC- mediated increases in AhR, Sp1, and Nrf2 levels within the ABCG2 promoter, markedly downregulated ABCG2, and inhibited proliferation and tumorigenicity of lung and esophageal cancer cells. Microarray analyses revealed that mithramycin targeted multiple stem cell–related pathways in vitro and in vivo. Collectively, our findings provide a potential mechanistic link between smoking status and outcome of patients with lung and esophageal cancers, and support clinical use of mithramycin for repressing ABCG2 and inhibiting stem cell signaling in thoracic malignancies.
    [Show full text]
  • Osrrm, a Spen-Like Rice Gene Expressed Specifically in the Endosperm
    Shi-Yan Chen et al. npg Cell Research (2007) 17:713-721. npg713 © 2007 IBCB, SIBS, CAS All rights reserved 1001-0602/07 $ 30.00 ORIGINAL ARTICLE www.nature.com/cr OsRRM, a Spen-like rice gene expressed specifically in the endosperm Shi-Yan Chen1, 2, Zong-Yang Wang1, Xiu-Ling Cai1 1National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China; 2Graduate School of the Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100039, China We used the promoter trap technique to identify a rice plant, named 107#, in which the β-glucuronidase (GUS) reporter gene was expressed specifically in the endosperm. A single copy of the T-DNA was inserted into the plant genome, and a candidate gene OsRRM was identified by the insertion. The OsRRM promoter directed GUS expression specifically in rice endosperm, analogous to the GUS expression pattern observed in 107#. OsRRM is a single-copy gene in rice and encodes a nuclear protein containing 1 005 amino-acid residues with two RNA recognition motifs and one Spen paralog and ortholog C-terminal domain. Western blot analysis confirmed that the OsRRM protein was specifically expressed in rice endosperm. Ectopic expression of OsRRM in transgenic plants led to abnormalities, such as short stature, retarded growth and low fructification rates. Our data, in conjunction with the reported function ofSpen genes, implicated OsRRM in the regulation of cell development in rice endosperm. Keywords: RRM, Spen, promoter trap, GUS, rice Cell Research (2007) 17:713-721.
    [Show full text]
  • The Estrogen Receptor Cofactor SPEN Functions As a Tumor Suppressor and Candidate Biomarker of Drug Responsiveness in Hormone-Dependent Breast Cancers
    Author Manuscript Published OnlineFirst on August 21, 2015; DOI: 10.1158/0008-5472.CAN-14-3475 Author manuscripts have been peer reviewed and accepted for publication but have not yet been edited. SPEN is a tumor suppressor in ERα positive breast cancers Title The estrogen receptor cofactor SPEN functions as a tumor suppressor and candidate biomarker of drug responsiveness in hormone-dependent breast cancers. Running Title SPEN is a tumor suppressor in ERα positive breast cancers Authors and affiliations: Légaré, Stéphanie1,2, Cavallone, Luca2, Mamo, Aline2, Chabot, Catherine2, Sirois, Isabelle1,2, Magliocco, Anthony3, Klimowicz, Alexander3, Tonin, Patricia N.4, Buchanan, Marguerite2, Keilty, Dana1,2, Hassan, Saima1,2, Laperrière, David5, Mader, Sylvie5,6, Aleynikova, Olga2, Basik Mark1,2 Keywords - Transcriptional corepressor - Tumor suppressor gene - Estrogen receptor positive breast cancers - Endocrine resistance Financial support • Stéphanie Légaré • Supported by a McGill Integrated Cancer Research Training Program studentship (FRN53888) and a doctoral award from the Fonds de recherche du Québec – Santé. • Isabelle Sirois • Recipient of the Eileen Iwanicki postdoctoral fellowship in Breast Cancer Research from the Canadian Institutes of Health Research in partnership with the Breast Cancer Society of Canada. 1 Dept of Surgery and Oncology, McGill University, Montréal, Québec, Canada. 2 Dept of Oncology and Surgery, Lady Davis Institute for Medical Research, Montréal, Québec, Canada. 3 Dept of Pathology, University of Calgary, Calgary, Alberta, Canada. 4 Depts of Human Genetics and Medicine, McGill University and The Research Institute of the McGill University Health Centre, Montréal, Québec, Canada. 5 Institut de recherche en immunologie et cancérologie, IRIC, Montréal, Québec, Canada. 6 Dept de Biochimie, Université de Montréal, Montréal, Québec, Canada.
    [Show full text]
  • SPEN Protein Expression and Interactions with Chromatin in Mouse Testicular Cells
    156 3 REPRODUCTIONRESEARCH SPEN protein expression and interactions with chromatin in mouse testicular cells Joanna Korfanty1, Tomasz Stokowy2, Marek Chadalski1, Agnieszka Toma-Jonik1, Natalia Vydra1, Piotr Widłak1, Bartosz Wojtaś3, Bartłomiej Gielniewski3 and Wieslawa Widlak1 1Maria Sklodowska-Curie Institute – Oncology Center, Gliwice Branch, Gliwice, Poland, 2Department of Clinical Science, University of Bergen, Bergen, Norway and 3Laboratory of Molecular Neurobiology, Neurobiology Center, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland Correspondence should be addressed to W Widlak; Email: [email protected] Abstract SPEN (spen family transcription repressor) is a nucleic acid-binding protein putatively involved in repression of gene expression. We hypothesized that SPEN could be involved in general downregulation of the transcription during the heat shock response in mouse spermatogenic cells through its interactions with chromatin. We documented predominant nuclear localization of the SPEN protein in spermatocytes and round spermatids, which was retained after heat shock. Moreover, the protein was excluded from the highly condensed chromatin. Chromatin immunoprecipitation experiments clearly indicated interactions of SPEN with chromatin in vivo. However, ChIP-Seq analyses did not reveal any strong specific peaks both in untreated and heat shocked cells, which might suggest dispersed localization of SPEN and/or its indirect binding to DNA. Using in situ proximity ligation assay we found close in vivo associations of SPEN with MTA1 (metastasis-associated 1), a member of the nucleosome remodeling complex with histone deacetylase activity, which might contribute to interactions of SPEN with chromatin. Reproduction (2018) 156 195–206 Introduction However, regulation of osteocalcin expression by SPEN depends on its interactions with other proteins.
    [Show full text]
  • 1 a Genome-Wide RNA Interference Screen Identifies New Regulators Of
    Downloaded from genome.cshlp.org on September 30, 2021 - Published by Cold Spring Harbor Laboratory Press A genome-wide RNA interference screen identifies new regulators of androgen receptor function in prostate cancer cells Keren Imberg-Kazdan1 Susan Ha1,2 Alex Greenfield3 Christopher S. Poultney3^ Richard Bonneau3 Susan K. Logan1,2,4 Michael J. Garabedian2, 3,4 Departments of Biochemistry and Molecular Pharmacology1, Urology2, Microbiology4, and NYU Cancer Institute5, New York University School of Medicine, 550 First Avenue, New York, NY 10016; 3Center for Genomics and Systems Biology, New York University, New York, New York 10003 ^ present address: Seaver Autism Center for Research and Treatment, Department of Psychiatry, Mount Sinai Medical Center, New York, New York 10029 Corresponding Author: Michael J. Garabedian Department of Microbiology NYU School of Medicine 550 First Avenue, New York, NY 10016 Phone 212 263-7662 Fax 212 263-8276 Email: [email protected] Running Title: Genome-wide RNAi screen for AR regulators Keywords: Androgen receptor, RNAi screen, transcriptional regulation, HIPK2, MED19, Mediator complex, prostate cancer 1 Downloaded from genome.cshlp.org on September 30, 2021 - Published by Cold Spring Harbor Laboratory Press Abstract The androgen receptor (AR) is a mediator of both androgen-dependent and castration- resistant prostate cancers. Identification of cellular factors affecting AR transcriptional activity could in principle yield new targets that reduce AR activity and combat prostate cancer, yet a comprehensive analysis of the genes required for AR-dependent transcriptional activity has not been determined. Using an unbiased genetic approach that takes advantage of the evolutionary conservation of AR signaling, we have conducted a genome-wide RNAi screen in Drosophila cells for genes required for AR transcriptional activity and applied the results to human prostate cancer cells.
    [Show full text]
  • A Conserved Structural Motif Reveals the Essential Transcriptional Repression Function of Spen Proteins and Their Role in Developmental Signaling
    Downloaded from genesdev.cshlp.org on September 29, 2021 - Published by Cold Spring Harbor Laboratory Press A conserved structural motif reveals the essential transcriptional repression function of Spen proteins and their role in developmental signaling Mariko Ariyoshi and John W.R. Schwabe1 Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 2QH, UK Spen proteins regulate the expression of key transcriptional effectors in diverse signaling pathways. They are large proteins characterized by N-terminal RNA-binding motifs and a highly conserved C-terminal SPOC domain. The specific biological role of the SPOC domain (Spen paralog and ortholog C-terminal domain), and hence, the common function of Spen proteins, has been unclear to date. The Spen protein, SHARP (SMRT/HDAC1-associated repressor protein), was identified as a component of transcriptional repression complexes in both nuclear receptor and Notch/RBP-J␬ signaling pathways. We have determined the 1.8 Å crystal structure of the SPOC domain from SHARP. This structure shows that essentially all of the conserved surface residues map to a positively charged patch. Structure-based mutational analysis indicates that this conserved region is responsible for the interaction between SHARP and the universal transcriptional corepressor SMRT/NCoR (silencing mediator for retinoid and thyroid receptors/nuclear receptor corepressor. We demonstrate that this interaction involves a highly conserved acidic motif at the C terminus of SMRT/NCoR. These findings suggest that the conserved function of the SPOC domain is to mediate interaction with SMRT/NCoR corepressors, and that Spen proteins play an essential role in the repression complex. [Keywords: SHARP; SPOC domain; Spen proteins; transcriptional corepressor; crystal structure; nuclear receptor] Received March 31, 2003; revised version accepted June 3, 2003.
    [Show full text]
  • Counteracting MDM2-Induced HIPK2 Downregulation Restores HIPK2/P53
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector FEBS Letters 584 (2010) 4253–4258 journal homepage: www.FEBSLetters.org Counteracting MDM2-induced HIPK2 downregulation restores HIPK2/p53 apoptotic signaling in cancer cells ⇑ ⇑⇑ Lavinia Nardinocchi a, , Rosa Puca a,b, David Givol c, Gabriella D’Orazi a,b, a Department of Experimental Oncology, Molecular Oncogenesis Laboratory, National Cancer Institute ‘‘Regina Elena”, 00158 Rome, Italy b Department of Oncology and Experimental Medicine, School of Medicine, University ‘‘G. d’Annunzio”, 66100 Chieti, Italy c Department of Molecular Cell Biology, The Weizmann Institute of Science, 76100 Rehovot, Israel article info abstract Article history: Homeodomain-interacting protein kinase-2 (HIPK2) is a crucial regulator of p53 apoptotic function Received 23 July 2010 by phosphorylating serine 46 (Ser46) in response to DNA damage. In tumors with wild-type p53, its Revised 21 August 2010 tumor suppressor function is often impaired by MDM2 overexpression that targets p53 for proteaso- Accepted 10 September 2010 mal degradation. Likewise, MDM2 targets HIPK2 for protein degradation impairing p53-apoptotic Available online 16 September 2010 function. Here we report that zinc antagonised MDM2-induced HIPK2 degradation as well as p53 Edited by Gianni Cesareni ubiquitination. The zinc inhibitory effect on MDM2 activity leads to HIPK2-induced p53Ser46 phos- phorylation and p53 pro-apoptotic transcriptional activity. These results suggest that zinc deriva- tives are potential molecules to target the MDM2-induced HIPK2/p53 inhibition. Keywords: HIPK2 Ó 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
    [Show full text]
  • Ski and Snon, Potent Negative Regulators of TGF-Β Signaling
    Cell Research (2009) 19:47-57. npg © 2009 IBCB, SIBS, CAS All rights reserved 1001-0602/09 $ 30.00 REVIEW www.nature.com/cr Ski and SnoN, potent negative regulators of TGF-β signaling Julien Deheuninck1, Kunxin Luo1 1UC Berkeley, Department of Molecular and Cellular Biology, 16 Barker Hall, MC3204, Berkeley, CA 94720, USA Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fi- broblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identified in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated. Keywords: SnoN, Ski, Signal transduction, development, tumorigenesis, TGF-β signaling, senescence Cell Research (2009) 19:47-57. doi: 10.1038/cr.2008.324; published online 30 December 2008 Introduction sion of Fussel-18 and Fussel-15 appears to be limited to neuronal tissues, suggesting that their functions may be The sno gene (Ski novel gene) was initially discov- more restricted. ered on the basis of its close homology to v-ski, the Ski and SnoN contain several structural domains (Fig- transforming component of the Sloan–Kettering virus ure 1), including the DHD (Dachshund homology do- (SKV) [1] and its cellular homolog c-ski [2].
    [Show full text]
  • Loss of HIPK2 Protects Neurons from Mitochondrial Toxins by Regulating Parkin Protein Turnover
    The Journal of Neuroscience, January 15, 2020 • 40(3):557–568 • 557 Cellular/Molecular Loss of HIPK2 Protects Neurons from Mitochondrial Toxins by Regulating Parkin Protein Turnover X Jiasheng Zhang,1,2 Yulei Shang,1 Sherry Kamiya,1 Sarah J. Kotowski,3,4 XKen Nakamura,3,4 and XEric J. Huang1,2 1Department of Pathology, University of California, San Francisco, San Francisco, California 94143, 2Pathology Service 113B, VA Medical Center, San Francisco, California 94121, 3Department of Neurology, University of California, San Francisco, San Francisco, California 94122, and 4Gladstone Institute of Neurological Disease, San Francisco, California 94158 Mitochondria are important sources of energy, but they are also the target of cellular stress, toxin exposure, and aging-related injury. Persistent accumulation of damaged mitochondria has been implicated in many neurodegenerative diseases. One highly conserved mechanism to clear damaged mitochondria involves the E3 ubiquitin ligase Parkin and PTEN-induced kinase 1 (PINK1), which cooper- atively initiate the process called mitophagy that identifies and eliminates damaged mitochondria through the autophagosome and lysosome pathways. Parkin is a mostly cytosolic protein, but is rapidly recruited to damaged mitochondria and target them for mi- tophagy. Moreover, Parkin interactomes also involve signaling pathways and transcriptional machinery critical for survival and cell death. However, the mechanism that regulates Parkin protein level remains poorly understood. Here, we show that the loss of homeodo- main interacting protein kinase 2 (HIPK2) in neurons and mouse embryonic fibroblasts (MEFs) has a broad protective effect from cell death induced by mitochondrial toxins. The mechanism by which Hipk2 Ϫ / Ϫ neurons and MEFs are more resistant to mitochondrial toxins is in part due to the role of HIPK2 and its kinase activity in promoting Parkin degradation via the proteasome-mediated mecha- nism.
    [Show full text]
  • Prolyl Isomerase Pin1 and Protein Kinase HIPK2 Cooperate To
    Cell Death and Differentiation (2014) 21, 321–332 & 2014 Macmillan Publishers Limited All rights reserved 1350-9047/14 www.nature.com/cdd Prolyl isomerase Pin1 and protein kinase HIPK2 cooperate to promote cortical neurogenesis by suppressing Groucho/TLE:Hes1-mediated inhibition of neuronal differentiation R Ciarapica1,2, L Methot1, Y Tang1,RLo1, R Dali1, M Buscarlet1, F Locatelli2,3, G del Sal4,5, R Rota2 and S Stifani*,1 The Groucho/transducin-like Enhancer of split 1 (Gro/TLE1):Hes1 transcriptional repression complex acts in cerebral cortical neural progenitor cells to inhibit neuronal differentiation. The molecular mechanisms that regulate the anti-neurogenic function of the Gro/TLE1:Hes1 complex during cortical neurogenesis remain to be defined. Here we show that prolyl isomerase Pin1 (peptidyl-prolyl cis-trans isomerase NIMA-interacting 1) and homeodomain-interacting protein kinase 2 (HIPK2) are expressed in cortical neural progenitor cells and form a complex that interacts with the Gro/TLE1:Hes1 complex. This association depends on the enzymatic activities of both HIPK2 and Pin1, as well as on the association of Gro/TLE1 with Hes1, but is independent of the previously described Hes1-activated phosphorylation of Gro/TLE1. Interaction with the Pin1:HIPK2 complex results in Gro/TLE1 hyperphosphorylation and weakens both the transcriptional repression activity and the anti-neurogenic function of the Gro/ TLE1:Hes1 complex. These results provide evidence that HIPK2 and Pin1 work together to promote cortical neurogenesis, at least in
    [Show full text]